Trace Detection of SARS-CoV-2 N-Protein by Diamond Solution-Gate Field-Effect Transistor

Abstract

In this study, we introduced H-terminated diamond solution-gate field-effect transistor (H-diamond SGFET) to detect trace SARS-CoV-2 N-protein, which plays an important role in replication and transcription of viral RNA. 1-pyrenebutyric acid–N-hydroxy succinimide ester (Pyr-NHS) was modified on H-diamond surface as linker, on which the specific antibody of SARS-CoV-2 N-protein was catenated. Fourier transform infrared spectrum, scanning electron microscope and energy dispersive spectrum were utilized to demonstrate the modification of H-diamond with Pyr-NHS and antibody. Shifts of IDS(max) at VGS=-500 mV in transfer characteristics of H-diamond SGFET was observed to determine N-protein concentration in phosphate buffer solution. Good linear relationship between IDS(max) and log10(N-protein) was observed from 10-14 to 10-5 g/mL with goodness of fit R2=0.90 and sensitivity of 1.98 μA/Log10 [concentration of N-protein] at VDS=-500 mV, VGS=-500 mV. Consequently, this prepared H-diamond SGFET biosensor may provide a new idea for diagnosis of SARS-CoV-2 due to a wide detection range from 10-14 to 10-5 g/mL and low limit of detection 10-14 g/mL.

Note:

Funding Information: This work was supported by the Science and Technology Bureau of Xi'an (Grant No. XA2020-YXYJ-0105), Natural Science Basic Research Program of Shaanxi under Grant 2021JQ-062; National Key R&D Program of China (No. 2018YFE0125900), National Natural Science Foundation of China (No. 61627812，61804122 and 62074127), China Postdoctoral Science Foundation (No. 2019M660256 and 2020M683485), Key R&D Program of Shaanxi Province (No. 2021GY-223).

Declaration of Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Keywords: diamond, Solution-gate field-effect transistor, SARS-CoV-2 N-protein, Biosensor